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AVO VOLCANO ACTIVITY NOTIFICATION
(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued: (20181219/2035Z)
(3) Volcano: Semisopochnoi (VNUM #311060)
(4) Current Color Code: UNASSIGNED
(5) Previous Color Code: YELLOW
(6) Source: Alaska Volcano Observatory
(7) Notice Number:
(8) Volcano Location: N 51 deg 55 min E 179 deg 35 min
(9) Area: Aleutians
(10) Summit Elevation: 2625 ft (800 m)
(11) Volcanic Activity Summary: No eruptive activity has been detected at Semisopochnoi since November 1 when a satellite link for transmitting seismic data failed. Since that time, no changes have been observed in satellite data, and no explosions have been detected from the Adak Island infrasound array; the last explosion detected by infrasound was October 31.

AVO is lowering the Aviation Color Code to UNASSIGNED and Alert Level to UNASSIGNED for Semisopochnoi due to the lack of evidence for ongoing eruptive activity. Seismic unrest may be continuing undetected. Pauses in eruptions lasting weeks to months are known to occur during volcanic eruptions. A return to eruptive activity may occur with little or no warning.
(12) Volcanic cloud height: No cloud observed
(13) Other volcanic cloud information: No cloud observed
(14) Remarks: The seismic monitoring network for Semisopochnoi has been offline since November 1, but if atmospheric conditions permit an infrasound array on Adak Island may detect explosion signals from Semisopochnoi with a 13 minute delay. Semisopochnoi is also monitored remotely with satellite observations and lightning sensors.
(15) Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497


David Fee, Acting Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085
(16) Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu

AVO/USGS Volcanic Activity Notice

Volcano: Semisopochnoi (VNUM #311060)

Current Volcano Alert Level: UNASSIGNED
Previous Volcano Alert Level: ADVISORY

Current Aviation Color Code: UNASSIGNED
Previous Aviation Color Code: YELLOW

Issued: Wednesday, December 19, 2018, 11:35 AM AKST
Source: Alaska Volcano Observatory
Notice Number:
Location: N 51 deg 55 min E 179 deg 35 min
Elevation: 2625 ft (800 m)
Area: Aleutians

Volcanic Activity Summary: No eruptive activity has been detected at Semisopochnoi since November 1 when a satellite link for transmitting seismic data failed. Since that time, no changes have been observed in satellite data, and no explosions have been detected from the Adak Island infrasound array; the last explosion detected by infrasound was October 31.

AVO is lowering the Aviation Color Code to UNASSIGNED and Alert Level to UNASSIGNED for Semisopochnoi due to the lack of evidence for ongoing eruptive activity. Seismic unrest may be continuing undetected. Pauses in eruptions lasting weeks to months are known to occur during volcanic eruptions. A return to eruptive activity may occur with little or no warning.


Recent Observations:
[Volcanic cloud height] No cloud observed
[Other volcanic cloud information] No cloud observed

Remarks: The seismic monitoring network for Semisopochnoi has been offline since November 1, but if atmospheric conditions permit an infrasound array on Adak Island may detect explosion signals from Semisopochnoi with a 13 minute delay. Semisopochnoi is also monitored remotely with satellite observations and lightning sensors.

Contacts: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497


David Fee, Acting Coordinating Scientist, UAFGI
dfee1@alaska.edu (907) 322-4085

Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
http://www.avo.alaska.edu

The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.
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URL: www.avo.alaska.edu/activity/report.php
Page modified: December 2, 2016 10:12
Contact Information: AVO Web Team

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